Injury to Spawning Areas and an Evaluation of Spawning Escapement Enumeration of211 Pink Salmon in Prince William Sound, Alaska. EXXON VALDEZ Oil Spill State/Federal 211 Natural Resource Damage Assessment Final Report. Fish/Shellfish Study Number 1, 211 R

摘要

Fish-Shellfish Study Number 1 was designed to document oil contamination of211u001eintertidal spawning habitat and changes in the number and distribution of pink 211u001esalmon spawning in intertidal and upstream areas relative to oil contamination 211u001eresulting from the Exxon Valdez oil spill. No obvious effects on adult pink 211u001esalmon abundance, distribution, or histology were found. As other damage 211u001eassessment studies established injury to pink salmon embryos and juveniles, adult 211u001epink salmon restoration studies were initiated to evaluate and improve escapement 211u001eenumeration techniques to ensure that injured populations were adequately 211u001eprotected. Restoration Studies 9 and 60B focused on the main sources of error 211u001eaffecting accuracy and precision of escapement estimates generated by area-under-211u001ethe curve calculations, stream life and observer efficiency. Ground observer 211u001ecounts were found to tend to be more accurate than aerial observer counts, but 211u001eboth methods underestimated actual numbers of spawners. We obtained strong 211u001eevidence that escapement estimates based on appropriate streamlife and observer 211u001eefficiency values were more accurate and always greater than those based on the 211u001ecurrently used 17.5 day stream-life value and no observer efficiency adjustment.